A navigation device is generally stationed in a car or installed on board, and serves a driver as a means to check the present location and speed of a car by receiving precise microwave signals transmitted by plural satellites utilized by Global Positioning System (GPS). It is generally called “a navigation”. Such a navigation device displays on its screen the present position of a car which is calculated by use of GPS as well as map data retrieved from the memory device included therein, thereby enabling a user thereof to know the present location on the map in real time. In addition, a navigation device is able to search a path from a departure to a destination with waypoint data inputted by a user, and has a function to guide the user therewith by a means of voice or an image.
FIG. 1 is an embodiment of a method for showing an intersection enlargement image in a conventional navigation device.
A conventional navigation device provides a direction with an enlarged image at an intersection which is located in the course of a car, while the device is displaying a desired path on the screen, wherein the enlarged image can be two-dimensional or three-dimensional.
Conventional methods, however, have limitations in providing an exact direction at a complex intersection or interchange such as one with a multi-legs, an on/off-ramp of an expressway or a underpass. Failure to provide a driver with an exact direction guides the driver into a wrong direction.
Besides, conventional methods have a shortcoming in that it provides an intersection enlargement image calculating distance-to-go from the car's present spot without taking into account of the predicted time when to reach the intersection along with the present speed, thereby guiding a driver inexactly.